History

The patient is a 43-year-old white woman who had a convulsion at the age of 9 months in association with a high fever. Because of recurrent febrile convulsions, she was begun on mephobarbital at the age of 4 years.

On the first day of her first menstrual period, at the age of 11, she had her first afebrile seizure. Over the ensuing years, she experienced two different types of seizures at an average frequency of four times a month each. The first type consisted of the feeling that she is being forced or pushed down. This would last five seconds without postictal symptoms. The second type began without a warning: she lost consciousness and then was observed to stare for up to 30 seconds and then to fall abruptly to the ground, usually with no apparent rhythmic or tonic motor movements. She regained consciousness approximately 10–20 seconds later. Postictally, she was tired, hungry and frustrated.

Her past medical history was significant for an occipital hemorrhage secondary to a seizure–related head injury at the age of 26, ovarian cysts and a transiently positive antinuclear antibody that was thought to be secondary to phenytoin. Family history was negative for epilepsy. Her father died from a myocardial infarction.

Examination and investigations

The patient's general, cardiological and neurological examinations were unremarkable.

Because her seizures were medically intractable, she was admitted to the hospital for video-EEG monitoring to determine whether epilepsy surgery was possible. Her antiepileptic medications were tapered and several seizures of the second type described above were recorded while she was in bed. The ictal EEG recordings demonstrated electrographic seizure activity confined to the left anterior to mid-temporal region. In addition, electrocardiographic (ECG) monitoring showed progressive bradycardia leading to complete asystole for up to 14 seconds before a normal heart rate was resumed. The change in cardiac rhythm began after the initial clinical manifestations of the seizures (staring and unresponsiveness). The ECG findings prompted a cardiology consultation.

Diagnosis

Cardiological diagnosis was asystole secondary to enhanced vagal tone from the left temporal lobe-onset seizures.

Treatment and outcome

The patient underwent implantation of a dual-chamber pacemaker. Since then, she has continued to have both types of seizures but has not fallen to the ground in association with the second type. She has elected to defer epilepsy surgery at this time.

Commentary

This patient had medically refractory simple partial and complex partial seizures. The latter type was often associated with abrupt falling to the ground if she was standing during the seizure. Over the years, it was assumed that the patient's falls to the ground were a direct effect of the seizures on the strength and tone in her lower extremities. Only when she underwent ictal EEG monitoring did it become apparent that there was an alternative explanation – cardiac asystole. This conclusion is supported by the fact that she has not fallen since implantation of a cardiac pacemaker even though she continues to have the other typical manifestations of her seizures. Independent of her seizures, the patient had no other clinical evidence of cardiac arrhythmias.

Ictal-induced changes in heart rate and rhythm are among the many possible autonomic manifestations of seizures. 1 Sinus tachycardia is the most frequent disturbance of cardiac rate that accompanies seizures. 2 In one series of 12 consecutive patients with temporal lobe seizures, ictal tachycardia was associated with left-sided seizure onset in four patients and right temporal lobe onset in eight patients. 1

Bradyarrhythmias, including bradycardia, sinus arrest, atrioventricular block and asystole, occur much less frequently than tachyarrhythmias. 2–6 In some patients with ictal-induced bradyarrhythmia, loss of consciousness may be due to syncope and not to the seizure. In this patient, a change in consciousness (manifested by staring and unresponsiveness) preceded the change in heart rate, although it is likely that her falls were associated with cardiac asystole.

Recognition of the cardiovascular manifestations of seizures requires a high index of suspicion. This case illustrates that patients with abrupt falls following the onset of typical complex partial seizures should be evaluated for possible ictal-related cardiac conduction disturbances with simultaneous ECG and EEG monitoring.

What did I learn from this case?

I learned that a fall in conjunction with a seizure may result from cardiogenic syncope. In this case, the falls to the ground posed the risk of injury to the patient (as had happened, for example, with the traumatic occipital hemorrhage at the age of 26); moreover, the falls were preventable even if the seizures were not fully controlled. I also realized that I would have missed this diagnosis if the patient had not undergone simultaneous ECG and EEG monitoring.

How did this case alter my approach to the care and treatment of my epilepsy patients?

I now take a more thorough history from patients who fall as a result of their seizures about the circumstances immediately preceding the fall. Was there stiffening or muscle twitching? Was there facial pallor? Did someone take a pulse as the patient was falling or immediately before or after? If the answers are suggestive of cardiac arrhythmia as a cause for the falls, then I recommend simultaneous ECG and EEG monitoring and a cardiological consultation when appropriate.